Consensus on Overfilling Tanks?
- Thread starter rob.mwpropane
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happy-diver
Skindiver Just feelin it
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I'm always changing valves as I set my dozens of tanks different repurposings
Installed some Dacors on some current galvanised paint stripped Faber tanks
where I found out during 300bar testing that the tiniest, teeniest, smallest gap
permits the main O ring to extrude
I subsequently modified the tanks
Next is solder filling the disc plugs
White doesn't lend itself to vintage
Blue labelled Voit tanks look good
limits are set for a reason.
Some of us believe that because we are Divers, we know better than the gas industry or the government.
Fill your tanks, let them cool, and fill them again.
Alternatively, chain several tanks. The pressure grows slower, heating is less, pressure loss is less.
Blackcrusader
Contributor
One of the places I dive in Cebu where the temperature is often around 30C has their staff filling three tanks at a time. They will often fill hot to 220 bar and then let the tanks sit and cool. Sometimes I've picked up a tank to find less than 180 bar in it but not often.
They will top off any tank with less than 200 bar if asked. Most of the time now the tanks are at 210 bar or more cold. These are AL 80's I also own my own AL100 and leave it at the dive center. I use it for the extra weight and not for the extra air.
They will top off any tank with less than 200 bar if asked. Most of the time now the tanks are at 210 bar or more cold. These are AL 80's I also own my own AL100 and leave it at the dive center. I use it for the extra weight and not for the extra air.
Blackcrusader
Contributor
This thread seems to have gone off the rails from the original question. Why is it that a simple question gets derailed by people fighting over what qualifications they hold when they are not relevant to the OP's question. Who cares what tec or re-breather or instructor qualification you have? It seems that every time a person asks a simple question people come in touting their own qualifications that do nothing to answer the question. Especially with those holding "tec" or instructor level qualifications.
Reminds me of diving with a Spanish woman last November who was an OW Padi certified diver. Not very experienced but she was interested in the marine life. She was quite surprised at the quality photos and video's I had taken on my previous dive so she asked to buddy up with me. As she did not have a camera I said I would take some videos and photos of her on the dive and email them to her. A South African tec diver comes over telling her how qualified he is at everything and she should dive with a better certified diver. He assumed everyone in our group was only an OW qualified diver.
He had done "rescue" and knew all about CPR. He wants her to use one of his dive computers and she is not really interested in that either even though she doesn't have a dive computer. After she rebuffs his "advances" he goes on about his "rescue" skills some more to impress her. He finally gets around to asking her what she does for a living. She nonchalantly replies that she is an intestinal surgeon and operates on those who have bowel cancer and other serious aliments and that yes patients do sometimes need to be given CPR and defibrillator used to bring patients back to life.
Was so funny watching that "tec" diver know it all slink away.
What do I know about overfilling tanks? Not a lot. They are pressure tested usually to above 300 bar so I get mine filled to around 210 - 220 bar if possible. 200 bar is normal in most places I dive at but a lot of dive centers are happy to fill them to 210.
Reminds me of diving with a Spanish woman last November who was an OW Padi certified diver. Not very experienced but she was interested in the marine life. She was quite surprised at the quality photos and video's I had taken on my previous dive so she asked to buddy up with me. As she did not have a camera I said I would take some videos and photos of her on the dive and email them to her. A South African tec diver comes over telling her how qualified he is at everything and she should dive with a better certified diver. He assumed everyone in our group was only an OW qualified diver.
He had done "rescue" and knew all about CPR. He wants her to use one of his dive computers and she is not really interested in that either even though she doesn't have a dive computer. After she rebuffs his "advances" he goes on about his "rescue" skills some more to impress her. He finally gets around to asking her what she does for a living. She nonchalantly replies that she is an intestinal surgeon and operates on those who have bowel cancer and other serious aliments and that yes patients do sometimes need to be given CPR and defibrillator used to bring patients back to life.
Was so funny watching that "tec" diver know it all slink away.
What do I know about overfilling tanks? Not a lot. They are pressure tested usually to above 300 bar so I get mine filled to around 210 - 220 bar if possible. 200 bar is normal in most places I dive at but a lot of dive centers are happy to fill them to 210.
OP
Gosh, I feel like I stepped out of the theater for 5 min and that's when it got to the good stuff!
I really thought this was all simplified? Completely within standards to fill +10% (notice I didn't say overfill?). Working pressure changes with temperature and therefore the 70f rating printing on the side of the tank (in my case 3442psi) is just the working pressure at that temperature. ~ 130f is about in line with +10% and still the correct working pressure.
Why did certs get thrown in here....it's just math and standards?
BTW - Tank filling should follow "proper protocols". The same ones that are used for bar-b-que cooking. Low and slow. Patience is a virtue. But yes, you can "cheat". Understanding what you are doing is the point, and understanding where the real lines are to be drawn.
"Overfill/Cave fill" and "hot fill" are mutually different practices.
Blending is a whole additional chapter
Edit: And, @abnfrog taught me most of this (but not the BBQ part...)
"Overfill/Cave fill" and "hot fill" are mutually different practices.
Blending is a whole additional chapter
Edit: And, @abnfrog taught me most of this (but not the BBQ part...)
W W Meixner
Banned
Gosh, I feel like I stepped out of the theater for 5 min and that's when it got to the good stuff!
I really thought this was all simplified? Completely within standards to fill +10% (notice I didn't say overfill?). Working pressure changes with temperature and therefore the 70f rating printing on the side of the tank (in my case 3442psi) is just the working pressure at that temperature. ~ 130f is about in line with +10% and still the correct working pressure.
Why did certs get thrown in here....it's just math and standards?
Exactly...get extra butter
100days-a-year
Contributor
I have fond memories of dropping off 40ish tanks at various dive shops in the Keys, giving the tank monkeys a 6 pack or cash tip and then going shopping. My tanks were normally 3100 to 3200 for AL and low pressure steel , somewhat higher for high pressure steels.
I wonder what protocols they were using considering they were doing 6 at a time in a water bath.
Me personally, I fill them as rated or a bit above as needed.
I used to sweat it a lot but just bought larger tanks instead.
I wonder what protocols they were using considering they were doing 6 at a time in a water bath.
Me personally, I fill them as rated or a bit above as needed.
I used to sweat it a lot but just bought larger tanks instead.
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